Aluminum base alloy



Patented 12; 1939 I v UNITED STATES- PATENT OFFICE 2,183,391 Y I ALUMINUM BASE ALLOY No Drawing, Application August 30,1938, Se-

:iglq No. 227,594. In German! September 1,

3' Claims. (01. 15-14;

Aluminum and its alloys are, as w n n additite. In those cases where a corrosiondue exceedingly sensitive to the action of mercury. Salt Solution =mu$t be guarded which metal forms an almalgam with aluminum. 8 besides or s due to y. the This amalgam prevents the formation on the addition of mengehese'wlll be Preferable 1' the 5 aluminum of a dense closely adhering oxide film; reason mentioned above The total content o I in view of the base-metal characteristic or alu- I manganese a d pp r i th a oy should not minum, this oxide film constitutes the only promaterially exeeed 5 D eehttection which that metal has against the destruc- Besides, the resistance against corrosion caused tive efiect of air, oxygen or water. Because of y watery c os ve a e ts ca be further inthis, a piece of aluminum or aluminum alloy will, creased y an d t 01 illii-gheshlmrv metal 10 'once it has been in'contact with mercury, oxidize which i ea the} es a 01 a um much more rapidly when exposed to air, or will against these corrosive effects. However. as h be more quicklydestroyed when exposed to water. experiments on which the application is based In view of this, users are always cautioned against have e an addition 70! magnesium will ebringing amminum and m u alloys in crease at the same time the resistance with re- 15 tact with mercury, or against using aluminum B t0 mereul'yr their 18 0 s y. it p y 0558138 and aluminum alloys where there is a possibility the e the manganese P of contact with mercury due to operating di'stlvelv which has been added For this reesemthe turbances or accident. For instance, no mercury maximum magnesium addition cannot be resm'ted thermometers can be used in fermenting vats and must be satisfied with magnesium 20 which are made of aluminum, or special efiort contents or approximately cent: In this must be taken in order that when the thermommanner, all-9Y5 are tamed which are s eter is accidentally destroyed, the mercury will 1 mercury and Water: v they are 3' not come in contact with the aluminum. Up to Posed) nt1nuous simultaneous contact with the present it was out of the question to use aluthese agentsthat they can be used mt floats and minum or alluminum alloys in permanent consimilar parts- The alloy composition of 2 per tact with mercury and water, such as would he e magnesium Per cent 1 Per f manganese, iron and silicon in their usualrequired for the floats of some measuring instru limits, the remainder being aluminum, bas

ments. I It has been found surprisingly that such a proved to be well suited for the above purposes. contact a b well permitted n that com 4 If no danger of corrosion by'moist air orsalt tacts withaluminum alloys could be well applied exists. dditi n of magnesium may case the manganese and to such a purpose, provided the alloysare suitbe omitted and in this ably chosen. The required resistance to corroespecls-uy h Diem a be higher- A5 increase inthe general roslon is obtained by alloying to the aluminum in most cases where an metals such as copper, magnesium and mangaresistance is attained by means of alloy additions,

nese. The mere addition of copper is of con-' the Sensitivity with mpeet to a t at the S i siderable influence on the resistivity against merbouderies w increase. e with t a oys cury. An addition of one 0.1 per cent reduces which wehaveh stated- This' n at the 40 the oxide formation considerably, and with addi- 8 1 boilhdhl'ies can beeome pe y erous 0 tions of 0.5 per cent the alloy will be practically when t pa ts i e t are subject to interresistant to mercury the resistance increasing e Stresses wh ch originate either irom the castwith a further increase in the copper content, ing process or from the cold working. For this In these cases, however, where the alloy comes reason, such parts must be annealed prior to their simultaneously in contact with water or salt soluutilization so as to remove any internal tension. 5 tions, the eifect of higher copper additions cannot It is known that the resistance-with; r p to .be utilized, since it is known that the higher copmercury is raised by theaddition of copper,- but it per content considerably reduces the resistance to was not known that abmlutely perma ent allows corrosion in regard to watery solutions and moist can be obtained in this manner. It is also known "atmosphere. I

Manganese acts along the same llnes-as copper. is increased by the addition or magnesiumrbui: An addition of 1 per cent of manganese may be it was not known that the simultaneous additionconsidered as equivalent to an addition oi 0.5 of copper andmagnesium, possibly together with per cent oi copper. If both elements are added manganese, will create alloys which remain quite i simultaneously, their eflects become apparently stable even when exposed to simultaneous conthat'the resistance with respect to salt solutions order to give additional protection to the parts which have been alloyed according to the above data, an additional suriace protection may be procured by means of oxidation, which may be accomplished with or without electric current.

What we claim as new and desire to secure by Letters Patent of the United States, is:-

1. Analuminum base alloy subject to oxidizing conditions and contact with mercury, said'alloy containing more than 0.3 per cent butnot more than 1.5% copper, more than 0.3 per cent manganese, and remainder of said alloy consistingoi aluminum} and the total content of copper and manganese being not greater than 5 per cent by weight of the alloy.

0.5 to 4 per cent magnesium, the- 2. An aluminum base alloy subject to oxidizing conditions and contact with mercury, said alloy conditions and contact with mercury, saidalloy containing 0.3 per cent but not more than 1.5 per cent copper, at least 0.3 per cent manganese, the total. content of copper and manganese being not greater than 5 per cent by weight of said alloy. the. remainder of said alloy consisting of aluminum.

. 1 OTTO DAHL.

HERBERT DAILMANN.

Patent NO. 82 18515 CERTIFICATE OF CORRECTION.

- 7 December 12, 19 9.

0 0 DAHL, ET A It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1;, first column, line 5', for almalgam read amalgain; line 26, for "alluminum" reaq alfiminiam; line 59, for the word "one" read only; same page, second. column, Iirie 58, for "boudariea" read. boundaries; line'hB, for "allows" read alloys;

and that the' said Letter Patent should be readwii :h this correction ther- 4 in that the same may conform to the record of'the case inthe Patent Office.

Signed. and. sealed this 50th day of January; A. 13. 19m.

. Henry Van Arsdale, (S l) 7 Acting Commissioner of Patents. 

